After wheat absorbs water, the endosperm strength decreases. Starch and protein contained in endosperm are intertwined. Protein has strong water absorption capacity (large water absorption capacity) and slow water absorption speed; Starch granules have weak water absorption capacity (small water absorption capacity) and fast water absorption speed. Because of the different water absorption speed and capacity, different expansion sequence and degree, starch and protein particles are displaced, which makes the endosperm structure loose and reduces its strength, and it is easy to be ground into powder by the mill, which is beneficial to reducing the power consumption of the mill.